This invention concerns a device to capture the relative position of a component of which the position can change relative to a reference component of a washing handling device, in particular a washing machine or drier, and a corresponding washing handling device.
Such devices are known in various forms from the prior art. Thus the document DE 101 04 682 A1 shows a capacitive sensor, with which the axial distance of a tub relative to the housing of a washing machine is provided for the purpose of determining an imbalance, deflection in operation and the present loading of the washing drum. This solution has the disadvantage that capacitive sensors, in the context of the distances to be measured, are relatively difficult to evaluate, and are also subject to electromagnetic interference effects of the environment.
Another arrangement is known from the document DE 103 34 572 B3. In the case of the arrangement described in this document, a coil-based electromagnetic travel sensor is used to capture the deflection of the tub relative to the housing. Such electromagnetic travel sensors too are subject to interference effects and wear problems.
The document DE 698 07 055 T3 describes a washing machine where the present drum deflection and loading are determined using a Hall element and a magnet body associated with it. In this case, there is the problem that Hall sensors too are subject to electromagnetic interference, and to obtain sufficiently good measurement results, large, homogeneous magnets are required. Use of Hall sensors also has the disadvantage that to determine the present position in space, 3 field vectors are always required. Use of a single dipole magnet is not enough, since its field component is not biunique.
In the document DE 199 60 847 A1, the possibility of using strain gauges to determine the position of the tub in the housing of a washing machine is described. To evaluate the signals provided by strain gauges, relatively expensive and sensitive amplifier and compensation circuits are required.
The document DE 10 2004 043 752 B4 describes a measuring device with optical sensors to determine the present deflection of an axis of rotation of a washing drum relative to the tub of a washing machine. The optical system described in it has the disadvantage that it must be integrated into the bearing arrangement of the drum, and this is structurally expensive.